The Effects of Anesthetic Induced Loss of Consciousness on Quantitative Electroen Cephalogram, and Bispectral and Spectral Entropy Indices. Studies on Healthy Male

Changes in the electroencephalography (EEG) signal have been used to study the effects of anesthetic agents on the brain function. Several commercial EEG based anesthesia depth monitors have been developed to measure the level of the hypnotic component of anesthesia. Specific anesthetic related changes can be seen in the EEG, but still it remains difficult to determine whether the subject is consciousness or not during anesthesia. EEG reactivity to external stimuli may be seen in unconsciousness subjects, in anesthesia or even in coma. Changes in regional cerebral blood flow, which can be measured with positron emission tomography (PET), can be used as a surrogate for changes in neuronal activity. The aim of this study was to investigate the effects of dexmedetomidine, propofol, sevoflurane and xenon on the EEG and the behavior of two commercial anesthesia depth monitors, Bispectral Index (BIS) and Entropy. Slowly escalating drug concentrations were used with dexmedetomidine, propofol and sevoflurane. EEG reactivity at clinically determined similar level of consciousness was studied and the performance of BIS and Entropy in differentiating consciousness form unconsciousness was evaluated. Changes in brain activity during emergence from dexmedetomidine and propofol induced unconsciousness were studied using PET imaging. Additionally, the effects of normobaric hyperoxia, induced during denitrogenation prior to xenon anesthesia induction, on the EEG were studied. Dexmedetomidine and propofol caused increases in the low frequency, high amplitude (delta 0.5-4 Hz and theta 4.1-8 Hz) EEG activity during stepwise increased drug concentrations from the awake state to unconsciousness. With sevoflurane, an increase in delta activity was also seen, and an increase in alpha- slow beta (8.1-15 Hz) band power was seen in both propofol and sevoflurane. EEG reactivity to a verbal command in the unconsciousness state was best retained with propofol, and almost disappeared with sevoflurane. The ability of BIS and Entropy to differentiate consciousness from unconsciousness was poor. At the emergence from dexmedetomidine and propofol induced unconsciousness, activation was detected in deep brain structures, but not within the cortex. In xenon anesthesia, EEG band powers increased in delta, theta and alpha (8-12Hz) frequencies. In steady state xenon anesthesia, BIS and Entropy indices were low and these monitors seemed to work well in xenon anesthesia. Normobaric hyperoxia alone did not cause changes in the EEG. All of these results are based on studies in healthy volunteers and their application to clinical practice should be considered carefully.

Mythology as a key to historical ways of thinking

Kirjallisuusarvostelu

Negotiating home and belonging. Young Kurds in Finland

This study looks at negotiation of belonging and understandings of home among a generation of young Kurdish adults who were born in Iraq, Iran, and Turkey and who reached adulthood in Finland. The young Kurds taking part in the study belong to the generation of migrants who moved to Finland in their childhood and early teenage years from the region of Kurdistan and elsewhere in the Middle East, then grew to adulthood in Finland. In theoretical terms, the study draws broadly from three approaches: transnationalism, intersectionality, and narrativity. Transnationalism refers to individuals’ cross-border ties and interaction extending beyond nationstates’ borders. Young people of migrant background, it has been suggested, are raised in a transnational space that entails cross-border contacts, ties, and visits to the societies of departure. How identities and feelings of belonging become formed in relation to the transnational space is approached with an intersectional frame, for examination of individuals’ positionings in terms of their intersecting attributes of gender, age/generation, and ethnicity, among others. Focus on the narrative approach allows untangling how individuals make sense of their place in the social world and how they narrate their belonging in terms of various mechanisms of inclusion and exclusion, including institutional arrangements and discursive categorisation schemes. The empirical data for this qualitative study come from 25 semi-structured thematic interviews that were conducted with 23 young Kurdish adults living in Turku and Helsinki between 2009 and 2011. The interviewees were aged between 19 and 28 years at the time of interviewing. Interview themes involved topics such as school and working life, family relations and language-learning, political activism and citizenship, transnational ties and attachments, belonging and identification, and plans for the future and aspirations. Furthermore, data were collected from observations during political demonstrations and meetings, along with cultural get-togethers. The data were analysed via thematic analysis. The findings from the study suggest that young Kurds express a strong sense of ‘Kurdishness’ that is based partially on knowing the Kurdish language and is informed by a sense of cultural continuity in the diaspora setting. Collective Kurdish identity narratives, particularly related to the consciousness of being a marginalised ‘other’ in the context of the Middle East, are resonant in young interviewees’ narrations of ‘Kurdishness’. Thus, a sense of ‘Kurdishness’ is drawn from lived experiences indexed to a particular politico-historical context of the Kurdish diaspora movements but also from the current situation of Kurdish minorities in the Middle East. On the other hand, young Kurds construct a sense of belonging in terms of the discursive constructions of ‘Finnishness’ and ‘otherness’ in the Finnish context. The racialised boundaries of ‘Finnishness’ are echoed in young Kurds’ narrations and position them as the ‘other’ – namely, the ‘immigrant’, ‘refugee’, or ‘foreigner’ – on the basis of embodied signifiers (specifically, their darker complexions). This study also indicates that young Kurds navigate between gendered expectations and norms at home and outside the home environment. They negotiate their positionings through linguistic repertoires – for instance, through mastery of the Finnish language – and by adjusting their behaviour in light of the context. This suggests that young Kurds adopt various forms of agency to display and enact their belonging in a transnational diaspora space. Young Kurds’ narrations display both territorially-bounded and non-territorially-bounded elements with regard to the relationship between identity and locality. ‘Home’ is located in Finland, and the future and aspirations are planned in relation to it. In contrast, the region of Kurdistan is viewed as ‘homeland’ and as the place of origins and roots, where temporary stays and visits are a possibility. The emotional attachments are forged in relation to the country (Finland) and not so much relative to ‘Finnishness’, which the interviewees considered an exclusionary identity category. Furthermore, identification with one’s immediate place of residence (city) or, in some cases, with a religious identity as ‘Muslim’ provides a more flexible venue for identification than does identifying oneself with the (Finnish) nation.

Alterations in The States and Contents of Consciousness: Empirical and Theoretical Aspects

The main purpose of the present doctoral thesis is to investigate subjective experiences and cognitive processes in four different types of altered states of consciousness: naturally occurring dreaming, cognitively induced hypnosis, pharmacologically induced sedation, and pathological psychosis. Both empirical and theoretical research is carried out, resulting in four empirical and four theoretical studies. The thesis begins with a review of the main concepts used in consciousness research, the most influential philosophical and neurobiological theories of subjective experience, the classification of altered states of consciousness, and the main empirical methods used to study consciousness alterations. Next, findings of the original studies are discussed, as follows. Phenomenal consciousness is found to be dissociable from responsiveness, as subjective experiences do occur in unresponsive states, including anaesthetic-induced sedation and natural sleep, as demonstrated by post-awakening subjective reports. Two new tools for the content analysis of subjective experiences and dreams are presented, focusing on the diversity, complexity and dynamics of phenomenal consciousness. In addition, a new experimental paradigm of serial awakenings from non-rapid eye movement sleep is introduced, which enables more rapid sampling of dream reports than has been available in previous studies. It is also suggested that lucid dreaming can be studied using transcranial brain stimulation techniques and systematic analysis of pre-lucid dreaming. For blind judges, dreams of psychotic patients appear to be indistinguishable from waking mentation reports collected from the same patients, which indicates a close resemblance of these states of mind. However, despite phenomenological similarities, dreaming should not be treated as a uniform research model of psychotic or intact consciousness. Contrary to this, there seems to be a multiplicity of routes of how different states of consciousness can be associated. For instance, seemingly identical time perception distortions in different alterations of consciousness may have diverse underlying causes for these distortions. It is also shown that altered states do not necessarily exhibit impaired cognitive processing compared to a baseline waking state of consciousness: a case study of time perception in a hypnotic virtuoso indicates a more consistent perceptual timing under hypnosis than in a waking state. The thesis ends with a brief discussion of the most promising new perspectives for the study of alterations of consciousness.

The neural processes generating visual phenomenal consciousness: ERP and neuronavigated brain stimulation studies

One of the greatest conundrums to the contemporary science is the relation between consciousness and brain activity, and one of the specifi c questions is how neural activity can generate vivid subjective experiences. Studies focusing on visual consciousness have become essential in solving the empirical questions of consciousness. Th e main aim of this thesis is to clarify the relation between visual consciousness and the neural and electrophysiological processes of the brain. By applying electroencephalography and functional magnetic resonance image-guided transcranial magnetic stimulation (TMS), we investigated the links between conscious perception and attention, the temporal evolution of visual consciousness during stimulus processing, the causal roles of primary visual cortex (V1), visual area 2 (V2) and lateral occipital cortex (LO) in the generation of visual consciousness and also the methodological issues concerning the accuracy of targeting TMS to V1. Th e results showed that the fi rst eff ects of visual consciousness on electrophysiological responses (about 140 ms aft er the stimulus-onset) appeared earlier than the eff ects of selective attention, and also in the unattended condition, suggesting that visual consciousness and selective attention are two independent phenomena which have distinct underlying neural mechanisms. In addition, while it is well known that V1 is necessary for visual awareness, the results of the present thesis suggest that also the abutting visual area V2 is a prerequisite for conscious perception. In our studies, the activation in V2 was necessary for the conscious perception of change in contrast for a shorter period of time than in the case of more detailed conscious perception. We also found that TMS in LO suppressed the conscious perception of object shape when TMS was delivered in two distinct time windows, the latter corresponding with the timing of the ERPs related to the conscious perception of coherent object shape. Th e result supports the view that LO is crucial in conscious perception of object coherency and is likely to be directly involved in the generation of visual consciousness. Furthermore, we found that visual sensations, or phosphenes, elicited by the TMS of V1 were brighter than identically induced phosphenes arising from V2. Th ese fi ndings demonstrate that V1 contributes more to the generation of the sensation of brightness than does V2. Th e results also suggest that top-down activation from V2 to V1 is probably associated with phosphene generation. The results of the methodological study imply that when a commonly used landmark (2 cm above the inion) is used in targeting TMS to V1, the TMS-induced electric fi eld is likely to be highest in dorsal V2. When V1 was targeted according to the individual retinotopic data, the electric fi eld was highest in V1 only in half of the participants. Th is result suggests that if the objective is to study the role of V1 with TMS methodology, at least functional maps of V1 and V2 should be applied with computational model of the TMS-induced electric fi eld in V1 and V2. Finally, the results of this thesis imply that diff erent features of attention contribute diff erently to visual consciousness, and thus, the theoretical model which is built up of the relationship between visual consciousness and attention should acknowledge these diff erences. Future studies should also explore the possibility that visual consciousness consists of several processing stages, each of which have their distinct underlying neural mechanisms.

Predicting bankruptcy of Finnish limited liability companies from historical financial statements

This master’s thesis studies the probability of bankruptcy of Finnish limited liability companies as a part of credit risk assessment. The main idea of this thesis is to build and test bankruptcy prediction models for Finnish limited liability companies that can be utilized in credit decision making. The data used in this thesis consists of historical financial statements from 2112 Finnish limited liability companies, half of which have filed for bankruptcy. A total of four models are developed, two with logistic regression and two with multivariate discriminant analysis (MDA). The time horizon of the models varies from 1 to 2 years prior to the bankruptcy, and 14 different financial variables are used in the model formation. The results show that the prediction accuracy of the models ranges between 81.7% and 88.9%, and the best prediction accuracy is achieved with the one year prior the bankruptcy logistic regression model. However the difference between the best logistic model and the best MDA model is minimal. Overall based on the results of this thesis it can be concluded that predicting bankruptcy is possible to some extent, but naturally the results are not perfect.

Finland's security in a changing Europe : a historical perspective

Finnish Defence Studies is published under the auspices of the National Defence College, and the contributions reflect the fields of research and teaching of the College. Finnish Defence Studies will occasionally feature documentation on Finnish Security Policy. Views expressed are those of the authors and do not necessarily imply endorsement by the National Defence College.